chore(project): initialize project with core configuration and dependencies

- Add .gitignore and .env.example files for project setup
- Create build script for proto compilation with tonic-prost
- Generate Cargo.lock with all project dependencies
- Configure project structure and ignore patterns for development environment

tests/email_tests.rs

@@ -0,0 +1,102 @@
+use emailks::{
+    email_build::build_message_from_parts,
+    error::EmailError,
+    pb::email::v1::{EmailAddress, SendEmailRequest},
+};
+use std::time::Duration;
+
+fn test_config() -> emailks::config::SmtpConfig {
+    emailks::config::SmtpConfig {
+        host: "localhost".into(),
+        port: 1025,
+        username: None,
+        password: None,
+        from_email: Some("sender@test.com".into()),
+        from_name: Some("Sender".into()),
+        reply_to: None,
+        tls: emailks::config::SmtpTls::None,
+        timeout: Duration::from_secs(5),
+        helo_name: None,
+        allow_request_from: false,
+    }
+}
+
+fn req_with_to(to: &str) -> SendEmailRequest {
+    SendEmailRequest {
+        from: None,
+        to: vec![EmailAddress {
+            email: to.into(),
+            name: String::new(),
+        }],
+        cc: vec![],
+        bcc: vec![],
+        subject: "Hello".into(),
+        text_body: "World".into(),
+        html_body: String::new(),
+        attachments: vec![],
+        priority: 0,
+        headers: Default::default(),
+        reply_to: String::new(),
+    }
+}
+
+#[test]
+fn sender_from_request() {
+    let mut cfg = test_config();
+    cfg.allow_request_from = true;
+    let mut req = req_with_to("to@test.com");
+    req.from = Some(EmailAddress {
+        email: "req@test.com".into(),
+        name: "Request".into(),
+    });
+
+    let msg = build_message_from_parts(&cfg, &req).unwrap();
+    let body = String::from_utf8(msg.formatted()).unwrap();
+    assert!(body.contains("From: Request <req@test.com>"));
+    assert!(body.contains("To: to@test.com"));
+    assert!(body.contains("Subject: Hello"));
+}
+
+#[test]
+fn sender_from_config() {
+    let mut req = req_with_to("to@test.com");
+    req.text_body = String::new();
+    req.html_body = "<p>Hi</p>".into();
+
+    let msg = build_message_from_parts(&test_config(), &req).unwrap();
+    let body = String::from_utf8(msg.formatted()).unwrap();
+    assert!(body.contains("From: Sender <sender@test.com>"));
+    assert!(body.contains("Content-Type: text/html"));
+}
+
+#[test]
+fn missing_sender_error() {
+    let mut cfg = test_config();
+    cfg.from_email = None;
+    let req = req_with_to("to@test.com");
+    let err = build_message_from_parts(&cfg, &req).unwrap_err();
+    assert!(matches!(err, EmailError::MissingSender));
+}
+
+#[test]
+fn missing_recipients_error() {
+    let req = SendEmailRequest {
+        from: Some(EmailAddress {
+            email: "x@x.com".into(),
+            name: String::new(),
+        }),
+        to: vec![],
+        cc: vec![],
+        bcc: vec![],
+        subject: "s".into(),
+        text_body: "b".into(),
+        html_body: String::new(),
+        attachments: vec![],
+        priority: 0,
+        headers: Default::default(),
+        reply_to: String::new(),
+    };
+
+    let err = build_message_from_parts(&test_config(), &req).unwrap_err();
+    assert!(matches!(err, EmailError::MissingRecipients));
+}